This invention relates generally to an improvement in a hatch cover for a miniature electrical device operated by a battery or button-type energy cell. More particularly, the invention relates to an improvement wherein such batteries are easily removable and replaceable without need for special tools or skill.
The miniaturization of electrical and electronic devices has been accompanied by the increased use of small batteries or button-type energy cells. For example, in electric or electronic watches, such batteries are usually held in place by a screw-thread hatch cover as exemplified in U.S. Pat. No. 3,916,613 issued Nov. 4, 1975 to Esselborn and assigned to the present assignee. Another type of hatch cover employs an interference fit and is pried off with a sharp instrument. This is a well known construction used by applicant's assignee and others. Batteries are also held in cavities or openings in structures contiguous to miniature electrical devices with connections for electrically connecting the device to the battery, as exemplified in U.S. Pat. No. 3,729,923 issued May 1, 1973 to Brigliano et al.
With the proliferation of miniature electrical and electronic devices in the consumer area, it has become increasingly important to facilitate replacement of batteries without the need for special skill or instruments. Most of the known hatch covers make direct electrical contact between the back of the button cell and the hatch cover and make contact on the other end between a projection on the cell and the contact spring. In this manner the case is used as the ground and must be conductive.
In some applications, the case may be of non-conductive material such as plastic or, as indicated in the aforementioned Brigliano et al. patent, the enclosure containing the battery may be of insulating material, requiring two spring contacts for making electrical connections.
In either event, close fits and small battery size often make removal of the battery difficult for the average consumer. In some cases, inappropriate instruments will be used for removal of the energy cell causing damage to the electrical device.
Accordingly, one object of the present invention is to provide an improved battery hatch cover which facilitates removal and replacement of the battery.
Another object of the invention is to provide an improved battery hatch cover which permits non-conductive cases or enclosures for the battery of a small electrical or electronic device.